1. Field of the invention
The present invention relates to thread guide devices of a sewing machine.
2. Prior Art
Conventional thread guide devices are shown in FIGS. 10 and 11. In this sewing machine, threads 52a such as looper threads, needle threads are threaded in the following manner, namely, firs fly setting thread spools 52 on spool pins respectively provided upright on a spool holder stand 50, hanging the threads 52a extended from the thread spools 52 on thread guides 53a of thread guide holder 53, threading the threads 52a into thread guide holes 55a of thread guide plate 55, inserting the threads 52a which are passed through the thread guide holes 55a into silt-shaped thread guide grooves 55b so as to be retained by recesses 55c, inserting the threads 52a into guide grooves 54a of a body 54, clamping the threads 52a between tension discs of tension devices provided at the front portion of the body 54, and threading the threads 52a into loopers, needles, etc., while the threads 52a are pulled downward.
However, the following are problems in the conventional thread guide devices.
(1) Since each thread 52a is sequentially threaded in each thread guide hole 55a of thread guide plate 55 and each thread guide groove 55b, and it is retained by each recess 55c, the threading operation is difficult and takes time.
(2) Since the thread 52a is guided while it is retained by the recess 85c, it is liable to come off not only when the thread guide 53a of the thread guide holder 53 is raised or lowered but also when the thread 52a is moved irregularly. As a result, a given tension necessary for the sewing operation can not be applied to the thread 52a.
(3) Since the upper portion of the thread guide plate 55 must protrude from the body 54 because of the threading of the thread 52a into the thread guide hole 55a, the thread 52a extended from the thread guide 53a is easily entangled with the thread guide plate 55 not only when the thread guide 53a of the thread guide holder 53 is raised or lowered but also when the thread 52a is moved irregularly.